1. Field of the Invention
This invention relates generally to tables of the class which are referred to as benches and more particularly to an improved so-called rolling bench and an improved roller glide system therefor.
2. Prior Art
A bench in the class to which this invention pertains is essentially a relatively long and narrow table having a base and a platform top supported on the base. Benches of this kind are used for a variety of purposes. One widespread application of such benches is supporting or storing plants in greenhouses. The rolling bench of the present invention is particularly adapted for such greenhouse use and will be described in this context. It will become evident as the description proceeds, however, that the invention is not limited to this particular application.
Greenhouses commonly contain a large number of benches for holding plants. These benches are arranged in long rows with aisles between adjacent rows through which persons may walk to provide access to all areas of the benches. Such aisles, of course, consume valuable floor space which is limited by the overall dimensions of the greenhouse.
In order to conserve floor space, so-called rolling benches were devised. A rolling bench is simply a relatively long narrow table or bench whose platform top is supported on the base for edgewise movement laterally of the base between limiting positions wherein the top projects beyond one side or the other of the base. This edgewise adjustability of the top permits a substantial increase in the total square foot bench top area which can be accommodated within a given greenhouse floor area.
More particularly, with fixed top greenhouse benches, the width of each aisle is the space between the adjacent edges of the bench tops at opposite sides of the aisle. Maximum total bench top area for a given greenhouse floor area can be achieved only by making the aisles as narrow as possible and making the bench tops of the maximum width which will permit all areas of the top to be reached from the aisles. The width of the bench base is immaterial as long as it does not project beyond the edges of the bench top.
With a rolling bench, the bench top is adjustable laterally of the base. Maximum total of bench top area is achieved by making the bench top of the maximum width which will permit all areas of the top to be reached from one adjacent aisle or the other and making the width of the base no greater than this maximum top width minus the minimum desired aisle width. The benches at opposite sides of each aisle are located with their bases spaced a distance equal to the desired aisle width.
Each bench top is adjustable laterally of its base between two limiting positions. At each limiting position, one longitudinal side of the top is substantially flush with the adjacent sides of the base and hence clears the adjacent aisle between the bench and the bench at the opposite side of the aisle. The opposite longitudinal side of the bench top projects beyond its adjacent side of the base a distance equal to the difference between the width of the top and the width of the base and across the adjacent aisle.
Consider now a greenhouse having several rows of such rolling benches with aisles between the adjacent rows. Access to any given aisle is achieved by moving the top of the benches at opposite sides of the given aisle away from one another to their opposite limiting positions. This, of course, requires that the tops of the benches in the rows beyond those adjacent the given aisle must be moved outwardly to their corresponding limiting positions.
The net floor space saving achieved with such rolling benches is approximately equal to a number of aisle widths which is one less than the number of rows. Accordingly, the floor space saving can be substantial in large greenhouses.
This invention overcomes certain deficiencies of the existing rolling benches and more particularly the deficiencies of the roller glide systems which support the bench top on the base for adjustment laterally of the base. A typical existing roller glide system for a rolling bench comprises a pair of long slender cylindrical rollers, such as pipes, disposed in substantially parallel relation between and in rolling contact with the bench base and top with the rollers extending lengthwise of the bench. During edgewise movement of the top laterally of the base, these rollers undergo relative rolling movement across the upper side of the base and the underside of the top along the direction line of movement of the top relative to the base.
When the bench top is adjusted to either of its limiting positions, the top projects cantilever fashion beyond the adjacent sides of the base. The downward force on the extending portion of the top, which force, of course, equals the weight of this extending portion plus any plants or the like on the top, produces a tilting moment on the platform tending to lower its extending edge portion and elevate its opposite inboard edge portion which overlies the base. This moment is counteracted by anti-tilt means on the platform which engage the base to restrain the top against tilting.
As noted above, this invention overcomes certain inherent deficiencies in the existing roller bench glide systems. One of these deficiencies resides in the fact that the existing glide system rollers are not restrained against lateral rolling movement relative to one another. As a consequence, when the bench top is moved to either limiting position, its inboard edge portion raises slightly and out of contact with the adjacent inboard glide roller. This frees the inboard roller to roll laterally relative to the other glide roller. Generally, the freed inboard glide roller rolls toward the side of the bench beyond which the bench top projects and thereby toward the other, outboard glide roller. This prevents the top from rolling freely in the opposite direction to its opposite limiting position, particularly when the top is heavily loaded with plants.
Another deficiency of the existing rolling bench glide system involves the anti-tilt means for the bench top. In the existing rolling bench system, this anti-tilt means comprises surfaces on the bench top which engage surfaces on the bench base upon initial tilting movement of the top so as to prevent further tilting of the top. In either limiting positions of the top, these anti-tilt surfaces engage with substantial contact pressure and must slide relative to one another upon inward movement of the top from its current limiting position. This sliding contact of the anti-tilt surfaces creates substantial friction which opposes inward movement of the top, particularly when the top is heavily loaded with plants. In many cases, this friction may be so great as to totally prevent movement of the top from its current limiting position